diff --git a/pkg/morph/client/notary.go b/pkg/morph/client/notary.go
index 069c35782..7399c19cd 100644
--- a/pkg/morph/client/notary.go
+++ b/pkg/morph/client/notary.go
@@ -412,16 +412,11 @@ func (c *Client) NotarySignAndInvokeTX(mainTx *transaction.Transaction) error {
 		return err
 	}
 
-	// error appears only if client
-	// is in inactive mode; that has
-	// been already checked above
-	magicNumber, _ := c.MagicNumber()
-
 	// mainTX is expected to be pre-validated: second witness must exist and be empty
 	mainTx.Scripts[1].VerificationScript = multiaddrAccount.GetVerificationScript()
 	mainTx.Scripts[1].InvocationScript = append(
 		[]byte{byte(opcode.PUSHDATA1), 64},
-		multiaddrAccount.PrivateKey().SignHashable(uint32(magicNumber), mainTx)...,
+		multiaddrAccount.SignHashable(c.rpcActor.GetNetwork(), mainTx)...,
 	)
 
 	//lint:ignore SA1019 https://git.frostfs.info/TrueCloudLab/frostfs-node/issues/202
@@ -667,12 +662,12 @@ func (c *Client) notaryWitnesses(invokedByAlpha bool, multiaddr *wallet.Account,
 	// to pass Notary module verification
 	var invokeScript []byte
 
-	magicNumber, _ := c.MagicNumber()
+	magicNumber := c.rpcActor.GetNetwork()
 
 	if invokedByAlpha {
 		invokeScript = append(
 			[]byte{byte(opcode.PUSHDATA1), 64},
-			multiaddr.PrivateKey().SignHashable(uint32(magicNumber), tx)...,
+			multiaddr.SignHashable(magicNumber, tx)...,
 		)
 	} else {
 		// we can't provide alphabet node signature
@@ -694,7 +689,7 @@ func (c *Client) notaryWitnesses(invokedByAlpha bool, multiaddr *wallet.Account,
 		// then we have invoker witness
 		invokeScript = append(
 			[]byte{byte(opcode.PUSHDATA1), 64},
-			c.acc.PrivateKey().SignHashable(uint32(magicNumber), tx)...,
+			c.acc.SignHashable(magicNumber, tx)...,
 		)
 
 		w = append(w, transaction.Witness{